As represented by, for example, a television game set and a personal computer, a data processing system so adapted as to read out program data (game program data in the case of the television game set) from an external memory and execute the same to display a predetermined image on a monitor device (for example, a CRT and a liquid crystal display device) and output a sound thereto has been conventionally known.
In such a data processing system, the program data stored in the external memory should not be data unfairly copied. If the program data stored in the external memory is data unfairly copied, the profit of an owner of the copyright of the program data is damaged. In addition, if the program data unfairly copied is inferior in quality, a malfunction occurs in the data processing system, so that the profit of a user purchasing the external memory is damaged. Consequently, the program data must be strictly prevented from being unfairly copied.
As a method of preventing program data from being unfairly copied, the following methods have been conventionally known.
A first method is a method disclosed in U.S. Pat. No. 4,462,076 issued on Jul. 24, 1984. This method is a method of previously storing a character or character data representing an owner of the copyright in both a memory in a main unit and a memory in an external cartridge, comparing both the data, merely displaying data representing an owner of the copyright by a character if both the data coincide with each other and then, starting the execution of a game program.
A second method is a method disclosed in Japanese Patent Laid-Open Gazette No. 210562/1990 laid open on Aug. 21, 1990. This method is a method of previously storing first character data for displaying a trademark in an external memory unit and storing second character data corresponding to the first character data in an internal memory in an information processing unit, displaying the first character data on a monitor device when the external memory unit is mounted on the information processing unit, and collating the first and second character data to allow the execution of program data if both the data coincide with each other.
A third method is a method disclosed in Japanese Patent Laid-Open Gazette No. 296433/1986 laid open on Dec. 27, 1986 and Japanese Patent Laid-Open Gazette No. 3331/1987 laid open on Jan. 9, 1987. This third method is a method of respectively providing an information processing unit and an external storage with ICs for checking the adaptability of the external storage and establishing data communication between both the ICs to judge the adaptability of the external storage.
The first method is very complicated because the data representing an owner of the copyright stored in the memory in the main unit must be altered for each exchange of the external cartridge. Furthermore, in the first method, after the data representing an owner of the copyright stored in the memory in the main unit and the data representing an owner of the copyright stored in the memory in the external cartridge coincide with each other, the data representing an owner of the copyright is displayed on a monitor device. When both the data do not coincide with each other, therefore, nothing is displayed on the monitor device. Consequently, the first method gives a user a feeling of uneasiness that the television game set itself develops a fault when both the data do not coincide with each other.
The second method uses as collating data the character data for displaying a trademark. Therefore, the necessity of altering the collating data in the memory in the main unit for each exchange of the external memory unit as in the first method is eliminated. In the second method, however, a collating program executed by a CPU in the information processing unit is stored in a ROM in the information processing unit. Consequently, the second method has the disadvantage in that it cannot be carried out with respect to a game apparatus containing no ROM for storing such a collating program. The first method has the same disadvantage.
Furthermore, in the first and second methods, image data is used as collating data. Accordingly, the first and second methods have also the disadvantages in that the amount of data such as collating data and collating program data is increased, and time required for collating processing becomes long.
In the third method, the ICs for checking the adaptability of the external storage must be provided for both the information processing unit and the external storage. When an optical information recording medium (for example, a CD-ROM) on which data is so recorded as to be optically readable is used as the external storage, however, it is impossible to provide such a checking IC for the optical information recording medium. Furthermore, the third method has the disadvantage in that it cannot be carried out with respect to a game apparatus containing no checking IC, similarly to the first and second methods.
Therefore, an object of the present invention is to provide a data processing system which is available to check the adaptability of an optical information recording medium, can be applied to an information processing unit or an image processing unit which store no collating program already sold, and can prevent the appearance of an unfair optical information recording medium by making only an adaptable optical information recording medium usable.